Lori Verderame fears Americans are selling off their fortunes one garage sale at a time. Verderame, an antiques expert known as Dr. Lori, is waging a campaign to educate people about the unrecognized treasures gathering dust in attics and populating yard and garage sales. She shares her expertise on the Discovery Channel series Auction Kings and in a nationally syndicated column.

Verderame often sees objects go for a fraction of their value, because the sellers don't recognize their worth. Often the culprit is ignorance, she said, but sometimes the root is more sinister.

She recalled meeting one woman of about 75 who had been duped into selling a document to an appraiser who'd valued it at $50. The document, it turned out, was worth $50,000.

That incident prompted Verderame to start doing shows to educate people about the potential value of their possessions. She presents the information with a generous dose of humor to help people retain what they've learned, she said in a recent phone interview from her office in Pennsylvania.

The fast-talking Verderame came to antiques appraising from museum work, where she would be called on to determine the value not only of artwork, but also of other donated items. She holds a doctorate in art history from Pennsylvania State University and has worked at institutions including the Yale University Art Gallery, Penn State's Palmer Museum of Art and the Allentown Art Museum.

She'd planned to be a university professor and concentrate on research, she said, but then someone from a Philadelphia television station saw one of her presentations back when she was doing them at community colleges, night schools and the like. That led to her hosting a local show called Trash or Treasure? and eventually to her current position with Auction Kings, where she evaluates items for the Atlanta auction house Gallery 63.

She frequently travels across the country, presenting what she calls her antiques appraisal comedy show. In between her appearances, she evaluates items for clients who contact her through her website, drloriv.com. She also has a Facebook page, facebook.com/doctorlori.

Verderame said just about everyone has stuff in their homes that has value. Trouble is, the average person often can't distinguish the gems from the junk. That's why she emphasizes the importance of appraisals.

Verderame said she bases her valuations strictly on past sales, not on wishful thinking or on price guides that might be written by dealers looking to profit from their own artificially inflated prices. She isn't a dealer, so there's no possibility of a conflict of interest, she said.

That's one of the rules Verderame shares: Never have an appraisal done by someone who wants to buy the item from you. That person might set the value low in the hope of cashing in on a bargain from an unwitting seller.

Verderame estimated she appraises about 20,000 objects a year and said she constantly watches the antiques markets to keep up on values. "That doesn't mean I can't make a mistake. I'm a human being," she said.

And she's not afraid to tell someone an item is worthless. "People want the truth. . . . It's hard to be the person that says it's not worth much," but honesty is critical to her integrity, she said.

Of course, she'd rather give people good news. She's identified some real bonanzas — a Picasso drawing bought for $2 that was worth $50,000; a Degas purchased for $12 at a garage sale, which she valued at $100,000; a copper weather vane that a man salvaged from his grandmother's house, and that turned out to be worth enough to save the home from foreclosure.

. Fine art, jewelry, other precious metals and architectural elements such as lighting fixtures are most likely to be valuable. Don't ever give them away or sell them without first finding out their worth.

. Don't assume unsigned artwork has no worth. It might.

. Ugliness is a first clue to value. Just because you don't like an item doesn't mean it's worthless.

. For metal items, weight indicates quality.

. Books have value if they're in good condition and odor-free.

. The value of a toy increases if it's accompanied by the original box.

. Old glass Christmas ornaments are in demand.

. If an item is marked "collectible," it's not. Those items are made in such large quantities that they're too common.